textproduct: Quad Cities

KEY MESSAGES

- Temperatures will be noticeably warmer tonight through Thursday with high temperatures each day in the mid to upper 70s.

- A weak storm system will bring low chances (10 to 40%) for showers and storms late Tuesday afternoon and evening south of Interstate 80.

- Widespread showers and storms return Thursday into Friday morning. There is the potential for strong storms.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 226 PM CDT Mon Apr 20 2026

It will be turning warmer during the short term as high pressure shifts to the east and warm southerly flow takes over. Winds are forecast to remain gusty this evening with gusts up to 25 MPH are possible. It will be noticeably warmer on Tuesday with low temperatures ranging from the upper 40s north of Interstate 80 to the lower 50s south.

A weak shortwave is forecast to move through the northwesterly flow aloft Tuesday into Tuesday night. This will drive a cool front across the region during the afternoon. This front is forecast to stall near the Highway 34 corridor on Tuesday. High temperatures on Tuesday are forecast to be in the mid to upper 70s across the area. Moisture is shown pooling along the front with Forecast CAPE values of 500 to 1500 with 0 to 6 km shear around 30 knots but the atmosphere is capped in the lower levels and we are not outlooked for severe storms due to lower moisture and the capping inversion. Chance of precipitation are 10 to 40 % mainly along and south of Highway 30 late afternoon into the evening. If storms do develop in this environment, gusty thunderstorm winds and small hail will be the main threats. Low temperatures on Wednesday morning are forecast to range from the upper 40s north of Highway 30 to the upper 50s south of Interstate 80.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 226 PM CDT Mon Apr 20 2026

Ridging will be in place at the surface and aloft Wednesday with warm weather continuing across the region and dry conditions. High temperatures on Wednesday will be in the mid to upper 70s. There Will be gusty south winds across the region with gusts up to 20 MPH.

Attention then turns to Thursday into Friday, as a broad, upper- level trough develops over the western CONUS on Tuesday and slowly makes its way eastward, becoming more negatively tilted with time. Likely chances (70-90%) of showers and storms will increase Thursday afternoon and evening, and continue into Friday morning. This scenario has been consistent with bringing a surface cold front attendant to the trough, with a pre-frontal shortwave impulse ahead of the boundary. The convective parameter space still shows more modest instability and shear, with MLCAPE values around 500 to 1000 J/kg and deep-layer shear around 20 to 30 knots. The various machine learning severe weather probabilities still show notable values for our region (equivalent to a Slight Risk), likely owing to the stronger large-scale forcing.

As we go into next weekend, the upper-level trough does pass through the area, but a large upper-level low appears to take shape over south-central Canada, placing our region under broad cyclonic flow. This will bring generally cooler conditions, with periodic chances of showers and perhaps a few storms as a couple of mid-level shortwaves revolve around the upper low.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 619 PM CDT Mon Apr 20 2026

A partial decoupling of the lower atmosphere will occur with sunset but sporadic gusts up to 18 knots are possible. After 04z/21 LLWS will develop around 1.5 kft AGL plus/minus 200 feet with winds up to 45 knots. After 14z/21 the nocturnal inversion will break allowing gusts up to 25 knots in low level mechanical turbulence.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.